Gorilla Glue Auto

Yep, sure is normal. What is happening is that your plant is reusing elements from those leaves, such as carbs, sugars, amino acids etc, for it is more efficient to do so, rather than making these elements from new during flowering. This is also why it is so important not to defoliate your pants. Plus the reduction in energy production that is also caused by defoliation. Hope this helps,...... Organoman..

Judging from the photos this plant is past time to harvest so in this case waiting may bring you some amber trichomes but that also could risk THC levels, so this plant not saying the strain just may not go amber.